Re: [PATCH] sym53c8xx_2: Keep transfer negotiations valid (2.6.27.5)

[Aaro Koskinen <aaro.koskinen@nokia.com>]

Hello,

ext Tony Battersby wrote:
> On a device that negotiates asynchronous, this patch causes a WDTR
> exchange on every command (not just inquiry/request sense), even on
> devices that don't advertise wide support in the inquiry data.  This is
> unnecessary overhead, and may (in theory) cause problems for old devices
> that don't handle WDTR correctly.

Yes, this is overlooked in the patch. Also if there is no synch nego or 
WDTR is rejected, then check_nego flag will stay on forever.

> This patch forces either WDTR or PPR on every inquiry and request
> sense.  I think it would be better if the negotiation was skipped if the
> current agreement and the goal are both narrow/asynchronous; that way we
> don't try to negotiate at all for devices that don't support wide or sync.

[...]

> However, if the current agreement is 8-bit narrow and only the sync
> parameters need to be renegotiated, then I think it would be better to
> use SDTR only.  That way we don't rely on WDTR working in order to use
> SDTR successfully.

These are both valid points. I will update the patch.

A.